1. Field of the Invention
The present invention relates to a gasket and snap ring installation tool. In particular, the present invention relates to a tool for placing a gasket against an interior flange of a hollow tube such as a pipe or pipe fitting and installing a snap ring into an interior seating groove to secure the gasket in position. The United States Government has rights in this invention pursuant to Contract No. DE-AC09-89SR18035 between the U.S. Department of Energy and Westinghouse Savannah River Company.
2. Discussion of Background
When a gasket is placed against an interior flange of a pipe, pipe joint or pipe fitting, it is frequently secured in position by inserting an expandable spring ("snap ting") into a seating groove formed in the inner surface of the pipe. A cross-sectional view of such a gasket and snap ring installation is shown in FIG. 1. A pipe or pipe fitting 10 has a bore 12 and an interior flange or end surface 14. A fitting 16 with an inner surface 18 is positioned over pipe 10. Fitting 16 has an internal seating groove 20 formed in surface 18, dimensioned for receiving a snap ring, retaining ring, locking ring or the like. A gasket 30 is positioned against surface 14, and a snap ring 32 is inserted into seating groove 20. A typical snap ring 32 is shown in FIG. 2. Placement of ring 32 into groove 20 requires that the ring be compressed to a diameter somewhat smaller than the internal diameter of fitting 16, positioned inside fitting 16 approximately in the plane of groove 20, and released to spring into the groove.
A number of tools are available for installing snap rings, retaining rings and the like. Some tools use inner and outer cylindrical sleeves, biased by a spring so that when a force is exerted on the outer sleeve, the inner sleeve rams the ring into the seating groove (Millheiser, U.S. Pat. No. 3,995,360; Hogan, U.S. Pat. No. 2,422,549; Wurtzel, U.S. Pat. No. 2,885,770). Jensen (U.S. Pat. No. 3,030,700) incorporates a tapered member to expand the ring prior to insertion. Ethridge, et al. (U.S. Pat. No. 3,483,606) teaches a snap ring installation tool wherein the inner sleeve is rotated to impart the necessary force.
Other tools use a "gun" or trigger-type mechanism to impart the force required to insert the ting. For example, Conner (U.S. Pat. No. 3,268,993) and Barkan, et al. (U.S. Pat. No. 2,510,206) employ a handle in communication with an inner sleeve that transports the ring into the pipe. Martin, Jr., et al. (U.S. Pat. No. 3,177,565) also discloses a magazine that eliminates the hand loading of tings.
Both Seine (U.S. Pat. No. 2,357,139) and Turpin, et al. (U.S. Pat. No. 3,347,083) teach tools wherein the ring is placed in a hollow member and a removable handle is placed therein to push the ring into the pipe. Turpin, et al. further provides means whereby the ring is expanded as it travels the length of the transporting member. Erdmann (U.S. Pat. No. 2,840,892) shows a piston and plunger type arrangement with a magazine for loading the tings mechanically. Dorman (U.S. Pat. No. 705,564) teaches a machine for sealing bottles. The machine contains a lever that, when pulled, contracts an internal cylindrical member. This contraction causes an attached plunger to forcibly place a cork on the bottle top.
Despite the availability of these devices, gaskets and snap rings are frequently inserted manually or with the aid of hand tools such as pliers. To install gasket 30 and ring 32 as shown in FIG. 1, the operator holds gasket 30 against surface 14 with one hand while working ring 32 into position using the other hand. Installing a single gasket and snap ring can take as long as 10-15 minutes, an interval of time that may be of concern if the pipe normally carries toxic or radioactively hazardous materials. The gasket and ring may be damaged by the manipulation required for installation, adversely affecting their performance. In addition, some types of gaskets contain friable materials such as asbestos which, if damaged, may present additional hazards to the operator.
There is a need for a tool that can be used to quickly and easily install a gasket and snap ring. The tool should be simple to load, to operate, and to manufacture.